How to Build a Fractal Antenna for HD

If you are tired of the cost of cable TV, a high-gain fractal antenna may be provide an effective and inexpensive alternative. Since 2009, over-the-air television broadcasting is exclusively offered in digital and high-definition formats. If your HDTV has a digital antenna tuner, you can immediately receive free HD broadcast channels using an antenna. The fractal antenna's compact design allows it to be installed discretely, eliminating unsightly poles and wires.

Skill level:

Moderate

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Things you need

Project enclosure: 8 by 6 inches, 3 inches deep

Coaxial cable: 75-ohm with connectors, 8 feet long

Bare copper wire: 18-gauge, 4 feet long

Matching transformer: 300-ohm to 75-ohm rating

6 machine screws: 1/8-inch diameter, 1/2 inch long

6 machine screw nuts and washers: 1/8 inch

Eye bolt: 1/8-inch diameter, 1/2 inch long

Power drill and 1/8-inch bit

Screwdriver

Ruler

Permanent marker

Wire cutters

Protractor

Pliers

Small piece of twine

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Instructions

Preparation

1

Turn the project box upside down, with the long sides horizontal. Measure and mark a starting point 2 inches from the left and 2 1/2 inches from the top. Mark two additional points 2 inches and 4 inches to the right of this mark. Return to the starting point, and mark a point 1 inch down. Mark two additional points 2 inches and 4 inches to the right, directly below the upper marks. The marks should form a rectangular shape in the middle of the box.

2

Drill six, 1/8-inch holes in the box at the marks. Insert machine screws through the holes in the bottom of the box and loosely attach the screws with nuts and washers.

3

Cut the bare electrical wire into four 8-inch and two 6-inch lengths.

4

Measure and mark seven, 1-inch intervals from the end of a copper wire. Bend the wire at the 4-inch mark, forming a 60-degree angle. With this middle peak pointing up, bend two 60-degree valleys on either side, at the 3- and 5-inch marks. Bend two additional 60-degree peaks at the 2- and 6-inch marks. Bend the 1- and 7-inch marks at 60 degrees, forming two more valleys. The fractal shape of the wire should resemble a partial 3-pointed star, with two legs angled outwards. Perform this procedure with the remaining 8-inch wires.

Assembly

1

Mount the centre peak of each fractal-shaped wire on one of the four corner screws on the bottom of the box. The fractals mounted to the upper corner screws should be oriented with the legs pointing up. The fractal legs on the lower corner screws should be pointing down.

2

Connect a 6-inch wire across the three upper screws and a 6-inch wire across the three lower screws. Attach the fork terminals of the matching transformer to the upper and lower middle screws. Tighten the screws to the box, securing the wire assembly in place. Snip any excess wire.

3

Drill a 1/8-inch hole in a 6-inch side of the box. Fasten the eye bolt to the box and tie a loop of twine through the eye. Hang the antenna from the twine.

4

Attach the project box lid. Connect the fractal antenna to your HDTV using the coaxial cable.

Tips and warnings

If the project box lid is plastic, line the lid with aluminium foil to create a reflector for the antenna.